The MP2/TZVP geometries and the standard heats of formation at 0 and 298.15 K of 1,2- and 1,3-silatitanacyclobutanes and a number of smaller Ti- and/or Si-containing alkanes are calculated using the G2 model. The G2 procedure was suitably modified to allow for treatment of first-row transition elements and was directly applied to the reference compounds, which were subsequently connected to the two rings via the appropriate homodesmic reactions. The expected accuracy should be on the order of 3 kcal mol(-1). Bonding and structural characteristics are discussed in terms of Boys localized orbitals and Bader density analysis.